ES2020 BigInt

src/org/mozilla/javascript/InterpreterData.java

@@ -7,30 +7,28 @@
 package org.mozilla.javascript;
 
 import java.io.Serializable;
+import java.math.BigInteger;
 import java.util.Arrays;
-
 import org.mozilla.javascript.debug.DebuggableScript;
 
-final class InterpreterData implements Serializable, DebuggableScript
-{
+final class InterpreterData implements Serializable, DebuggableScript {
     private static final long serialVersionUID = 5067677351589230234L;
 
     static final int INITIAL_MAX_ICODE_LENGTH = 1024;
     static final int INITIAL_STRINGTABLE_SIZE = 64;
     static final int INITIAL_NUMBERTABLE_SIZE = 64;
+    static final int INITIAL_BIGINTTABLE_SIZE = 64;
 
-    InterpreterData(int languageVersion, String sourceFile,
-                    String encodedSource, boolean isStrict)
-    {
+    InterpreterData(
+            int languageVersion, String sourceFile, String encodedSource, boolean isStrict) {
         this.languageVersion = languageVersion;
         this.itsSourceFile = sourceFile;
         this.encodedSource = encodedSource;
         this.isStrict = isStrict;
         init();
     }
 
-    InterpreterData(InterpreterData parent)
-    {
+    InterpreterData(InterpreterData parent) {
         this.parentData = parent;
         this.languageVersion = parent.languageVersion;
         this.itsSourceFile = parent.itsSourceFile;
@@ -39,10 +37,10 @@ final class InterpreterData implements Serializable, DebuggableScript
         init();
     }
 
-    private void init()
-    {
+    private void init() {
         itsICode = new byte[INITIAL_MAX_ICODE_LENGTH];
         itsStringTable = new String[INITIAL_STRINGTABLE_SIZE];
+        itsBigIntTable = new BigInteger[INITIAL_BIGINTTABLE_SIZE];
     }
 
     String itsName;
@@ -52,6 +50,7 @@ private void init()
 
     String[] itsStringTable;
     double[] itsDoubleTable;
+    BigInteger[] itsBigIntTable;
     InterpreterData[] itsNestedFunctions;
     Object[] itsRegExpLiterals;
 
@@ -100,84 +99,70 @@ private void init()
     boolean declaredAsFunctionExpression;
 
     @Override
-    public boolean isTopLevel()
-    {
+    public boolean isTopLevel() {
         return topLevel;
     }
 
     @Override
-    public boolean isFunction()
-    {
+    public boolean isFunction() {
         return itsFunctionType != 0;
     }
 
     @Override
-    public String getFunctionName()
-    {
+    public String getFunctionName() {
         return itsName;
     }
 
     @Override
-    public int getParamCount()
-    {
+    public int getParamCount() {
         return argCount;
     }
 
     @Override
-    public int getParamAndVarCount()
-    {
+    public int getParamAndVarCount() {
         return argNames.length;
     }
 
     @Override
-    public String getParamOrVarName(int index)
-    {
+    public String getParamOrVarName(int index) {
         return argNames[index];
     }
 
-    public boolean getParamOrVarConst(int index)
-    {
+    public boolean getParamOrVarConst(int index) {
         return argIsConst[index];
     }
 
     @Override
-    public String getSourceName()
-    {
+    public String getSourceName() {
         return itsSourceFile;
     }
 
     @Override
-    public boolean isGeneratedScript()
-    {
+    public boolean isGeneratedScript() {
         return ScriptRuntime.isGeneratedScript(itsSourceFile);
     }
 
     @Override
-    public int[] getLineNumbers()
-    {
+    public int[] getLineNumbers() {
         return Interpreter.getLineNumbers(this);
     }
 
     @Override
-    public int getFunctionCount()
-    {
+    public int getFunctionCount() {
         return (itsNestedFunctions == null) ? 0 : itsNestedFunctions.length;
     }
 
     @Override
-    public DebuggableScript getFunction(int index)
-    {
+    public DebuggableScript getFunction(int index) {
         return itsNestedFunctions[index];
     }
 
     @Override
-    public DebuggableScript getParent()
-    {
-         return parentData;
+    public DebuggableScript getParent() {
+        return parentData;
     }
 
-    public int icodeHashCode()
-    {
+    public int icodeHashCode() {
         int h = icodeHashCode;
         if (h == 0) {
             icodeHashCode = h = Arrays.hashCode(itsICode);

src/org/mozilla/javascript/NativeBigInt.java

@@ -0,0 +1,223 @@
+/* -*- Mode: java; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.javascript;
+
+import java.math.BigInteger;
+import java.util.Arrays;
+
+/** This class implements the BigInt native object. */
+final class NativeBigInt extends IdScriptableObject {
+    private static final long serialVersionUID = 1335609231306775449L;
+
+    private static final Object BIG_INT_TAG = "BigInt";
+
+    static void init(Scriptable scope, boolean sealed) {
+        NativeBigInt obj = new NativeBigInt(BigInteger.ZERO);
+        obj.exportAsJSClass(MAX_PROTOTYPE_ID, scope, sealed);
+    }
+
+    NativeBigInt(BigInteger bigInt) {
+        bigIntValue = bigInt;
+    }
+
+    @Override
+    public String getClassName() {
+        return "BigInt";
+    }
+
+    @Override
+    protected void fillConstructorProperties(IdFunctionObject ctor) {
+        addIdFunctionProperty(ctor, BIG_INT_TAG, ConstructorId_asIntN, "asIntN", 2);
+        addIdFunctionProperty(ctor, BIG_INT_TAG, ConstructorId_asUintN, "asUintN", 2);
+
+        super.fillConstructorProperties(ctor);
+    }
+
+    @Override
+    protected void initPrototypeId(int id) {
+        if (id == SymbolId_toStringTag) {
+            initPrototypeValue(
+                    SymbolId_toStringTag,
+                    SymbolKey.TO_STRING_TAG,
+                    getClassName(),
+                    DONTENUM | READONLY);
+            return;
+        }
+
+        String s;
+        int arity;
+        switch (id) {
+            case Id_constructor:
+                arity = 1;
+                s = "constructor";
+                break;
+            case Id_toString:
+                arity = 0;
+                s = "toString";
+                break;
+            case Id_toLocaleString:
+                arity = 0;
+                s = "toLocaleString";
+                break;
+            case Id_toSource:
+                arity = 0;
+                s = "toSource";
+                break;
+            case Id_valueOf:
+                arity = 0;
+                s = "valueOf";
+                break;
+            default:
+                throw new IllegalArgumentException(String.valueOf(id));
+        }
+        initPrototypeMethod(BIG_INT_TAG, id, s, arity);
+    }
+
+    @Override
+    public Object execIdCall(
+            IdFunctionObject f, Context cx, Scriptable scope, Scriptable thisObj, Object[] args) {
+        if (!f.hasTag(BIG_INT_TAG)) {
+            return super.execIdCall(f, cx, scope, thisObj, args);
+        }
+        int id = f.methodId();
+        if (id == Id_constructor) {
+            if (thisObj == null) {
+                // new BigInt(val) throws TypeError.
+                throw ScriptRuntime.typeErrorById("msg.not.ctor", BIG_INT_TAG);
+            }
+            BigInteger val = (args.length >= 1) ? ScriptRuntime.toBigInt(args[0]) : BigInteger.ZERO;
+            // BigInt(val) converts val to a BigInteger value.
+            return val;
+
+        } else if (id < Id_constructor) {
+            return execConstructorCall(id, args);
+        }
+
+        // The rest of BigInt.prototype methods require thisObj to be BigInt
+        BigInteger value = ensureType(thisObj, NativeBigInt.class, f).bigIntValue;
+
+        switch (id) {
+            case Id_toString:
+            case Id_toLocaleString:
+                {
+                    // toLocaleString is just an alias for toString for now
+                    int base =
+                            (args.length == 0 || args[0] == Undefined.instance)
+                                    ? 10
+                                    : ScriptRuntime.toInt32(args[0]);
+                    return ScriptRuntime.bigIntToString(value, base);
+                }
+
+            case Id_toSource:
+                return "(new BigInt(" + ScriptRuntime.toString(value) + "))";
+
+            case Id_valueOf:
+                return value;
+
+            default:
+                throw new IllegalArgumentException(String.valueOf(id));
+        }
+    }
+
+    private static Object execConstructorCall(int id, Object[] args) {
+        switch (id) {
+            case ConstructorId_asIntN:
+            case ConstructorId_asUintN:
+                {
+                    int bits =
+                            ScriptRuntime.toIndex(args.length < 1 ? Undefined.instance : args[0]);
+                    BigInteger bigInt =
+                            ScriptRuntime.toBigInt(args.length < 2 ? Undefined.instance : args[1]);
+
+                    if (bits == 0) {
+                        return BigInteger.ZERO;
+                    }
+
+                    byte[] bytes = bigInt.toByteArray();
+
+                    int newBytesLen = (bits / Byte.SIZE) + 1;
+                    if (newBytesLen > bytes.length) {
+                        return bigInt;
+                    }
+
+                    byte[] newBytes =
+                            Arrays.copyOfRange(bytes, bytes.length - newBytesLen, bytes.length);
+
+                    int mod = bits % Byte.SIZE;
+                    switch (id) {
+                        case ConstructorId_asIntN:
+                            if (mod == 0) {
+                                newBytes[0] = newBytes[1] < 0 ? (byte) -1 : 0;
+                            } else if ((newBytes[0] & (1 << (mod - 1))) != 0) {
+                                newBytes[0] |= -1 << mod;
+                            } else {
+                                newBytes[0] &= (1 << mod) - 1;
+                            }
+                            break;
+                        case ConstructorId_asUintN:
+                            newBytes[0] &= (1 << mod) - 1;
+                            break;
+                    }
+                    return new BigInteger(newBytes);
+                }
+
+            default:
+                throw new IllegalArgumentException(String.valueOf(id));
+        }
+    }
+
+    @Override
+    public String toString() {
+        return ScriptRuntime.bigIntToString(bigIntValue, 10);
+    }
+
+    @Override
+    protected int findPrototypeId(Symbol k) {
+        if (SymbolKey.TO_STRING_TAG.equals(k)) {
+            return SymbolId_toStringTag;
+        }
+        return 0;
+    }
+
+    @Override
+    protected int findPrototypeId(String s) {
+        int id;
+        switch (s) {
+            case "constructor":
+                id = Id_constructor;
+                break;
+            case "toString":
+                id = Id_toString;
+                break;
+            case "toLocaleString":
+                id = Id_toLocaleString;
+                break;
+            case "toSource":
+                id = Id_toSource;
+                break;
+            case "valueOf":
+                id = Id_valueOf;
+                break;
+            default:
+                id = 0;
+                break;
+        }
+        return id;
+    }
+
+    private static final int ConstructorId_asIntN = -1,
+            ConstructorId_asUintN = -2,
+            Id_constructor = 1,
+            Id_toString = 2,
+            Id_toLocaleString = 3,
+            Id_toSource = 4,
+            Id_valueOf = 5,
+            SymbolId_toStringTag = 6,
+            MAX_PROTOTYPE_ID = SymbolId_toStringTag;
+
+    private BigInteger bigIntValue;
+}